Communication management system, communication management method, and computer program product

ABSTRACT

A communication management system manages communication terminals transmitting and receiving communication data. The system includes a session management unit configured to manage session identifying information and terminal identifying information in an associated manner, the session identifying information being used to identify a communication session being performed among a plurality of communication terminals and the terminal identifying information being used to identify each of the communication terminals; a receiving unit configured to receive, from a conversion system, terminal identifying information about a communication terminal that is being in communication, the conversion system mutually converting a communication scheme of communication data transmitted from one communication terminal and a communication scheme of communication data transmitted from another communication terminal; and a transmitting unit configured to transmit, to the conversion system, session identifying information that is associated with the received terminal identifying information in the session management unit.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of and claims thebenefit of priority under 35 U.S.C. §120 from U.S. application Ser. No.14/183,859, filed Feb. 19, 2014, which is based upon and claims thebenefit of priority under 35 U.S.C. §119 from Japanese PatentApplication No. 2013-039707 filed in Japan on Feb. 28, 2013, the entirecontents of both of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to management of a communication terminalthat transmits and receives certain communication data.

2. Description of the Related Art

With the recent demand to reduce the cost of business trips and the timethey take, telephone conversation systems that operate overcommunication networks, such as the Internet, have become widely used tohold teleconferences. An example of such a telephone conversation systemis where a teleconference can be achieved by transmitting and receivingimage data and sound data among a plurality of telephone conversationterminals (refer to Japanese Patent Application Laid-open No.2008-227577).

In another telephone conversation system, even when two or moretelephone conversation terminals are communicating with each other, athird telephone conversation terminal, which is different from the twoor more telephone conversation terminals, can join them (refer toJapanese Patent Application Laid-open No. 2012-191598).

However, if the communication scheme of the third telephonecommunication terminal, which tries to join the communication, isdifferent from the communication scheme of the other two or moretelephone communication terminals, the third telephone communicationterminal cannot join the communication.

SUMMARY OF THE INVENTION

There is a need to at least partially solve the problems in theconventional technology.

According to an aspect of the present invention, there is provided acommunication management system that manages communication terminalstransmitting and receiving communication data. The communicationmanagement system includes a session management unit configured tomanage session identifying information and terminal identifyinginformation in an associated manner, the session identifying informationbeing used to identify a communication session being performed among aplurality of communication terminals and the terminal identifyinginformation being used to identify each of the plurality ofcommunication terminals among which the communication session is beingperformed; a receiving unit configured to receive, from a conversionsystem, terminal identifying information about a communication terminalthat is being in communication, wherein the conversion system mutuallyconverts a communication scheme of communication data transmitted fromone communication terminal and a communication scheme of communicationdata transmitted from another communication terminal; and a transmittingunit configured to transmit, to the conversion system, sessionidentifying information that is associated with the terminal identifyinginformation received by the receiving unit in the session managementunit.

According to another aspect of the present invention, there is provideda communication management method that is performed by a communicationmanagement system that includes a session management unit configured tomanage session identifying information and terminal identifyinginformation in an associated manner, the session identifying informationbeing used to identify a communication session being performed among aplurality of communication terminals and the terminal identifyinginformation being used to identify each of the plurality ofcommunication terminals among which the communication session is beingperformed. The communication management method includes receiving, froma conversion system, terminal identifying information about acommunication terminal that is being in communication, wherein theconversion system mutually converts a communication scheme ofcommunication data transmitted from one communication terminal and acommunication scheme of communication data transmitted from anothercommunication terminal; reading, from the session management unit,session identifying information that is associated with the terminalidentifying information received; and transmitting, to the conversionsystem, the session identifying information read.

According to still another aspect of the present invention, there isprovided a non-transitory computer-readable medium that contains acomputer program that, when executed by a communication managementsystem that includes a session management unit configured to managesession identifying information and terminal identifying information inan associated manner, the session identifying information being used toidentify a communication session being performed among a plurality ofcommunication terminals and the terminal identifying information beingused to identify each of the plurality of communication terminals amongwhich the communication session is being performed, cause thecommunication management system to perform a method including:receiving, from a conversion system, terminal identifying informationabout a communication terminal that is being in communication, whereinthe conversion system mutually converts a communication scheme ofcommunication data transmitted from one communication terminal and acommunication scheme of communication data transmitted from anothercommunication terminal; reading, from the session management unit,session identifying information that is associated with the terminalidentifying information received; and transmitting, to the conversionsystem, the session identifying information read.

The above and other objects, features, advantages and technical andindustrial significance of this invention will be better understood byreading the following detailed description of presently preferredembodiments of the invention, when considered in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a telephone conversation systemaccording to an embodiment of the invention;

FIG. 2 is a conceptual diagram illustrating a communication state when atelephone conversation is achieved between telephone conversationterminals using the same communication scheme;

FIGS. 3A to 3C are conceptual diagrams illustrating image quality ofimage data transmitted and received in accordance with a scalable videocoding (SVC) standard in FIGS. 2 and 4;

FIG. 4 is a conceptual diagram illustrating a communication state when atelephone conversation is achieved between the telephone conversationterminals using different communication schemes;

FIG. 5 is a conceptual diagram illustrating the image quality of theimage data transmitted and received in accordance with an advanced videocoding (AVC) standard in FIG. 4;

FIG. 6 is a perspective view of the telephone conversation terminalaccording to the embodiment;

FIG. 7 is a hardware structure diagram of the telephone conversationterminal according to the embodiment;

FIG. 8 is a hardware structure diagram of a telephone conversationmanagement system, a relaying apparatus, a conversion system, a programsupply system, or a maintenance system according to the embodiment;

FIG. 9 is a functional block diagram of the telephone conversationterminal, the relaying apparatus, the telephone conversation managementsystem, and the conversion system included in the telephone conversationsystem of the embodiment;

FIG. 10 is a conceptual diagram illustrating a quality change managementtable;

FIG. 11 is a conceptual diagram illustrating a relaying apparatusmanagement table;

FIG. 12 is a conceptual diagram illustrating a terminal informationmanagement table;

FIG. 13 is a conceptual diagram illustrating a terminal state managementtable;

FIG. 14 is a conceptual view illustrating a destination list managementtable;

FIG. 15 is a conceptual diagram illustrating a session management table;

FIG. 16 is a conceptual diagram illustrating a conversion managementtable;

FIG. 17 is a conceptual diagram illustrating a quality management table;

FIG. 18 is a sequence diagram illustrating processing at a preparatorystage in which a preparation is made for starting a telephoneconversation between the terminals;

FIG. 19 is a sequence diagram illustrating a request for stating atelephone conversation;

FIG. 20 is a flowchart illustrating the determination on thecommunication scheme;

FIG. 21 is a sequence diagram illustrating processing to establish acommunication session before the telephone conversation is made betweentwo dedicated terminals;

FIG. 22 is a sequence diagram illustrating processing in which telephoneconversation data is transmitted and received between two dedicatedterminals;

FIG. 23 is a sequence diagram illustrating processing to establish thecommunication session before a telephone conversation is made betweenthe dedicated terminal and a non-dedicated terminal;

FIG. 24 is a sequence diagram illustrating processing in which thetelephone conversation data is transmitted and received between thededicated terminal and the non-dedicated terminal;

FIGS. 25A to 25C are conceptual diagrams illustrating the image qualityof the image data having been converted by the conversion system; and

FIG. 26 is a sequence diagram illustrating processing of causing anon-dedicated terminal to join a telephone conversation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Exemplary embodiments of the present invention are described below withreference to the accompanying drawings.

FIG. 1 is a schematic diagram of a telephone conversation system 1according to an embodiment. As illustrated in FIG. 1, the telephoneconversation system 1 includes a plurality of telephone conversationterminals (10 aa, 10 ab, etc.), displays (120 aa, 120 ab, etc.) for therespective telephone conversation terminals (10 aa, 10 ab, etc.), aplurality of relaying apparatuses (30 a, 30 b, and 30 c), a telephoneconversation management system 50, a conversion system 80, a programsupply system 90, and a maintenance system 100. The telephoneconversation system 1 can achieve a teleconference between remotelocations by communication of image data and sound data, which areexamples of telephone conversation data. A plurality of routers (70 a,70 b, 70 c, 70 d, 70 ab, and 70 cd) select an optimal route for thetelephone conversation data.

The telephone conversation terminals (10 aa, 10 ab, 10 ac, etc.), therelaying apparatus 30 a, and the router 70 a are connected to each otherwith a LAN 2 a so as to enable communication among them. The telephoneconversation terminals (10 ba, 10 bb, 10 bc, etc.), the relayingapparatus 30 b, and the router 70 b are connected to each other with aLAN 2 b so as to enable communication among them. The LANs 2 a and 2 bare connected to each other with a leased line 2 ab including the router70 ab so as to enable communication therebetween. The LANs 2 a and 2 band the leased line 2 ab are located in a certain area X. For example,the area X is any area in Japan and the LAN 2 a is located in a businessoffice in Tokyo while the LAN 2 b is located in a business office inOsaka.

The telephone conversation terminals (10 ca, 10 cb, 10 cc, etc.), therelaying apparatus 30 c, and the router 70 c are connected to each otherwith a LAN 2 c so as to enable communication among them. The telephoneconversation terminals (10 da, 10 db, 10 dc, etc.), the conversionsystem 80, and the router 70 d are connected to each other with a LAN 2d so as to enable communication among them. The LANs 2 c and 2 d areconnected to each other with a leased line 2 cd including the router 70cd so as to enable communication therebetween. The LANs 2 c and 2 d andthe leased line 2 cd are located in a certain area Y. For example, thearea Y is any area in the United States of America and the LAN 2 c islocated in a business office in New York while the LAN 2 d is located ina business office in Washington, D.C. The areas X and Y are connected toeach other with the routers (70 ab and 70 cd) through the Internet 2 iso as to enable communication therebetween.

Hereinafter, the “telephone conversation terminal” is simply expressedas the “terminal” while the “telephone conversation management system”is simply expressed as the “management system”. An arbitrary terminal inthe terminals (10 aa, 10 ab, etc.) is referred to as the “terminal 10”.An arbitrary display in the displays (120 aa, 120 ab, etc.) is referredto as the “display 120”. An arbitrary relaying apparatus in the relayingapparatuses (30 a, 30 b, and 30 c) is referred to as the “relayingapparatus 30”. A terminal that requests a start of a teleconference isexpressed as a “requester terminal” and another terminal that is adestination of the request (relay destination) is described as a“destination terminal”. An arbitrary router in the routers (70 a, 70 b,70 c, 70 d, 70 ab, and 70 cd) is referred to as the “router 70”.

The management system 50, the program supply system 90, and themaintenance system 100 are connected to the Internet 2 i. In theembodiment, the conversion system 80 is connected to the router 70 d inthe LAN 2 d in the area Y. The management system 50, the program supplysystem 90, and the maintenance system 100 may be disposed in the area Xor the area Y, or in any area other than the areas X and Y.

In the embodiment, the communication network 2 includes the LANs 2 a and2 b, the leased lines 2 ab and 2 cd, the Internet 2 i, and the LANs 2 cand 2 d. The communication network 2 may include a section in whichcommunication is performed wirelessly such as WiFi (Wireless Fidelity)or Bluetooth (registered trademark) besides the wired transmission.

Each of the terminal 10, the relaying apparatus 30, the managementsystem 50, the router 70, the conversion system 80, the program supplysystem 90, and the maintenance system 100 illustrated in FIG. 1 has anumber of four digits attached at the bottom. These numbers representcommonly used IP addresses in IPv4 in a simple manner. For example, theIP address of the terminal 10 aa is “1.2.1.3”. The IP address may beexpressed in IPv6 instead of IPv4. However, the explanation is madeusing IPv4 for simple explanation.

The terminals 10 may be used together in a telephone conversation madein the same room, or in a telephone conversation made between an outdoorsite and an indoor site or among the outdoor sites in addition to atelephone conversation made among a plurality of business offices and atelephone conversation made among different rooms in the same businessoffice. When the terminals 10 are used at an outdoor site, communicationis performed wirelessly using a mobile phone communication network, forexample.

Each terminal 10 illustrated in FIG. 1 enables a user to have atelephone conversation by transmitting and receiving telephoneconversation data. The terminal 10 is a teleconference terminal, forexample. In addition, the terminal 10 transmits and receives thetelephone conversation data using a certain communication scheme (a callcontrol scheme to connect or disconnect to a destination of a telephoneconversation and a coding scheme to convert the telephone conversationdata to an Internet protocol (IP) packet).

Examples of the call control scheme include protocols such as (1) asession initiation protocol (SIP), (2) H.323, (3) an extended SIP, (4) aprotocol of an instant messenger, (5) a protocol using a message methodof the SIP, (6) a protocol of internet relay chat (IRC), and (7) anextended version of the protocol of the instant messenger. The protocolof the instant messenger is used in (4-1) an extensible messagingpresence protocol (XMPP) or (4-2) ICQ (registered trademark), AIM(registered trademark), or Skype (registered trademark), for example.The extended version of the protocol of the instant messenger is Jingle,for example.

Of the terminals 10, a terminal 10 is expressed as a “dedicated terminalA” that uses a communication scheme in which the call control scheme isthe protocol of the instant messenger (or the extended version of theprotocol of the instant messenger) and the coding scheme is scalablevideo coding (SVC), for example. Of the terminals 10, a terminal 10 isexpressed as a “non-dedicated terminal D” that uses anothercommunication scheme in which at least one of the call control schemeand the coding scheme differs from those of the dedicated terminal A. Inthe embodiment, as an example of two terminals using differentcommunication schemes, the “dedicated terminal A” is described as aterminal manufactured, sold, or managed by a specific company while the“non-dedicated terminal D” is described as a terminal manufactured,sold, or managed by a company other than the specific company. Thereason for using the above mentioned example in the embodiment is thatterminals manufactured, sold, or managed by different companies usedifferent communication schemes in many cases. As an alternative exampleof the two terminals using different communication schemes, a newterminal may be defined as the “dedicated terminal A” while an oldterminal may be defined as the “non-dedicated terminal D” in terms ofthe manufactured dates or sold dates of terminals manufactured or soldby an identical company.

Each relaying apparatus 30 is a computer system that relays thetelephone conversation data between two or more terminals of theterminals 10. The management system 50 performs login authentication ofthe terminal 10 and manages a telephone conversation state of theterminal 10, a destination list, and a communication state of therelaying apparatus 30 in an integrated fashion, for example. Imagesrepresented by the image data may be moving images or still images, orboth moving and still images.

The conversion system 80 plays roles of a signaling gateway thatconverts a call control signal and a video/audio gateway that encodesthe telephone conversation data. The conversion system 80 is a gatewaythat mutually converts the communication scheme of the telephoneconversation data transmitted from the requester terminal and thecommunication scheme (the call control scheme and the coding scheme) ofthe telephone conversation data transmitted from the destinationterminal, and converts at least one of the call control scheme and thecoding scheme.

The program supply system 90 is a computer system that provides programsused in the respective ones of the terminal 10, the relaying apparatus30, the management system 50, the conversion system 80, and themaintenance system 100 to the respective ones through the communicationnetwork 2.

The maintenance system 100 is a computer system that performsmaintenance management or maintenance of at least one of the terminal10, the relaying apparatus 30, the management system 50, the conversionsystem 80, and the program supply system 90. For example, when themaintenance system 100 is installed domestically while the terminal 10,the relaying apparatus 30, the management system 50, the conversionsystem 80, or the program supply system 90 is installed overseas, themaintenance system 100 remotely performs the maintenance management orthe maintenance of at least one of the terminal 10, the relayingapparatus 30, the management system 50, the conversion system 80, andthe program supply system 90 through the communication network 2. Themaintenance system 100 also performs the maintenance, such as themanagement of a model number, a product serial number, a salesdestination, maintenance and inspection, or a failure history, of atleast one of the terminal 10, the relaying apparatus 30, the managementsystem 50, the conversion system 80, and the program supply system 90without using the communication network 2.

The following describes a first communication pattern to achieve atelephone conversation between two dedicated terminals A with referenceto FIGS. 2 and 3A to 3C. FIG. 2 is a conceptual diagram illustrating acommunication state when a telephone conversation is achieved betweenthe telephone conversation terminals that use the same communicationscheme.

In the first communication pattern as illustrated in FIG. 2, thetelephone conversation system 1 performs communication of the telephoneconversation data using H.264/SVC, which is a video encoding standard.Specifically, in the telephone conversation system 1 illustrated in FIG.2, a management communication session sei for transmitting and receivingvarious types of management information is established between therequester terminal serving as the dedicated terminal A and thedestination terminal serving as the dedicated terminal A through themanagement system 50. In addition, between the requester terminal andthe destination terminal, four communication sessions are establishedfor transmitting and receiving four pieces of high resolution imagedata, medium resolution image data, low resolution image data, and sounddata through the relaying apparatus 30.

In FIG. 2, the four communication sessions established between therequester terminal and the relaying apparatus 30 are expressed as afirst communication session sed1 for telephone conversation data. Thefour communication sessions established between the relaying apparatus30 and the destination terminal are expressed as a second communicationsession sed2 for telephone conversation data.

The following describes a resolution of an image of the image datahandled in the first communication pattern illustrated in FIG. 2 withreference to FIGS. 3A to 3C. FIGS. 3A to 3C are conceptual diagramsillustrating image quality of the image data transmitted and received inaccordance with the SVC standard illustrated in FIG. 2.

The image includes a low resolution image that is composed of 160 pixelsin width by 120 pixels in length as illustrated in FIG. 3A and serves asa base image, a medium resolution image composed of 320 pixels in widthby 240 pixels in length as illustrated in FIG. 3B, and a high resolutionimage composed of 640 pixels in width by 480 pixels in length asillustrated in FIG. 3C. Among them, when the image data is transmittedthrough a narrow bandwidth path, low image quality image data includingonly low resolution image data serving as the base image is relayed bythe relaying apparatus 30. When the bandwidth is relatively wide, mediumimage quality image data including the low resolution image data servingas the base image and the medium resolution image data are relayed bythe relaying apparatus 30. When the bandwidth is very wide, high imagequality image data including the low resolution image data serving asthe base image, the medium resolution image data, and high resolutionimage data is relayed by the relaying apparatus 30.

The following describes a second communication pattern to achieve atelephone conversation between the dedicated terminal A and thenon-dedicated terminal D with reference to FIGS. 4 and 5. FIG. 4 is aconceptual diagram illustrating a communication state when a telephoneconversation is achieved between the telephone conversation terminalsusing different communication schemes from each other.

In the second communication pattern as illustrated in FIG. 4, thetelephone conversation system 1 performs communication of the telephoneconversation data using H.264/SVC and H.264/AVC(advanced video coding),which are video encoding standards. Specifically, in the telephoneconversation system 1 illustrated in FIG. 4, a management communicationsession sei1 for transmitting and receiving various types of managementinformation is established between the requester terminal serving as thededicated terminal A and the destination terminal serving as thenon-dedicated terminal D through the management system 50. Between themanagement system 50 and the conversion system 80, a managementcommunication session sei2 for transmitting and receiving various typesof management information is established.

In addition, between the requester terminal (an example of a firstcommunication terminal) and the conversion system 80, four communicationsessions are established for transmitting and receiving four respectivepieces of high resolution image data, medium resolution image data, lowresolution image data, and sound data through the relaying apparatus 30in accordance with H.264/SVC. In FIG. 4, the four communication sessionsestablished between the requester terminal and the relaying apparatus 30are expressed as a first communication session sed11 for telephoneconversation data. The four communication sessions established betweenthe relaying apparatus 30 and the conversion system 80 are expressed asa second communication session sed12 for telephone conversation data.

Furthermore, two communication sessions are established between theconversion system 80 and the destination terminal (an example of asecond communication terminal) for transmitting and receiving tworespective pieces of medium resolution image data and sound data inaccordance with H.264/AVC. In FIG. 4, the two communication sessionsestablished between the conversion system 80 and the destinationterminal are expressed as a third communication session sed13 fortelephone conversation data.

The following describes the resolution of an image of the image datahandled in the second communication pattern illustrated in FIG. 4 withreference to FIGS. 3A to 3C and 5. FIG. 5 is a conceptual diagramillustrating the image quality of the image data transmitted andreceived in accordance with the AVC standard illustrated in FIG. 4.

In the first communication session sed11 and the second communicationsession sed12 illustrated in FIG. 4, three types of image data havingdifferent resolutions illustrated in FIGS. 3A to 3C are transmitted andreceived in the same manner as the first communication session sed1 andthe second communication session sed2 illustrated in FIG. 2. In thethird communication session sed13 illustrated in FIG. 4, the mediumresolution image data illustrated in FIG. 5 is transmitted and received.

Hardware Structure of Embodiment

A hardware structure of the embodiment is described below. FIG. 6 is aperspective view of the telephone conversation terminal according to theembodiment. As illustrated in FIG. 6, the terminal 10 includes a housing1100, an arm 1200, and a camera housing 1300. A front sidewall surface1110 of the housing 1100 includes an air intake surface (notillustrated) having a plurality of air intake holes. A rear sidewallsurface 1120 of the housing 1100 includes an air exhaust surface 1121having a plurality of air exhaust holes. As a result, external air atthe front of the terminal 10 can be taken in through the air intakesurface (not illustrated) and the air taken in can be exhausted towardthe rear of the terminal 10 through the air exhaust surface 1121. Aright sidewall surface 1130 of the housing 1100 has a sound-collectinghole 1131. The sound-collecting hole 1131 enables a built-in microphone114, which is described later, to collect sounds such as voices, othersounds, and noises.

An operation panel 1150 is formed on a side adjacent to the rightsidewall surface 1130 of the housing 1100. The operation panel 1150 isprovided with a plurality of operation buttons (108 a to 108 e), a powersource switch 109, and an alarm lamp 119, which are described later, andincludes a sound output surface 1151 having a plurality of sound outputholes through which a sound output from a built-in speaker 115, which isdescribed later, passes. In addition, a housing section 1160 is formedin a recess so as to house the arm 1200 and the camera housing 1300, ona side adjacent to a left sidewall surface 1140 of the housing 1100. Theright sidewall surface 1130 of the housing 1100 is provided with aplurality of connecting ports (1132 a to 1132 c) for electricallyconnecting cables to a display I/F 117, which is described later. Theleft sidewall surface 1140 of the housing 1100 is provided with aconnecting port (not illustrated) for electrically connecting a cable120 c for the display 120 to an external device connection I/F 118,which is described later.

In the following description, an arbitrary operation button in theoperation buttons (108 a to 108 e) is expressed as the “operation button108” while an arbitrary connecting port in the connecting ports (1132 ato 1132 c) is expressed as the “connecting port 1132”.

The arm 1200 is mounted on the housing 1100 with a torque hinge 1210such that the arm 1200 is rotatable with respect to the housing 1100 inthe up-down direction within a range of a tilt angle θ1 of 135 degrees.FIG. 6 illustrates the state when the tilt angle θ1 is 90 degrees. Thecamera housing 1300 includes a built-in camera 112, which is describedlater. The camera 112 can be used to image a user, a document, and aroom, for example. The camera housing 1300 has a torque hinge 1310. Thecamera housing 1300 is mounted on the arm 1200 with the torque hinge1310. The camera housing 1300 can rotate with respect to the arm 1200 inthe up-down and left-right directions within a range of a pan angle θ2of ±180 degrees when the angle is 0 degrees in the state illustrated inFIG. 6 and within a range of a tilt angle θ3 of ±45 degrees.

The relaying apparatus 30, the management system 50, the conversionsystem 80, the program supply system 90, and the maintenance system 100have the same outer appearances as typical servers and computers. Thedescription of their outer appearances is thus omitted.

FIG. 7 is a schematic diagram illustrating a hardware structure of theterminal according to the embodiment. As illustrated in FIG. 7, theterminal 10 of the embodiment includes a central processing unit (CPU)101 that controls operation of the terminal 10, a read only memory (ROM)102 that stores therein a program used to drive the CPU 101 such as aninitial program loader (IPL), a random access memory (RAM) 103 that isused as a working area of the CPU 101, a flash memory 104 that storestherein various types of data such as a program for the terminal 10, theimage data, and the sound data, a solid state drive (SSD) 105 thatcontrols reading of various types of data from or writing various typesof data into the flash memory 104 under the control of the CPU 101, amedia drive 107 that controls reading of data from or writing (storing)of data into a recording medium 106 such as a flash memory, theoperation buttons 108 operated when a destination of the terminal 10 isselected, for example, the power source switch 109 that switches on andoff of the power source of the terminal 10, and a network interface(I/F) 111 that performs data transmission using the communicationnetwork 2.

The terminal 10 further includes the built-in camera 112 that images asubject and acquires the image data under the control of the CPU 101, animage capturing device I/F 113 that controls driving of the camera 112,the built-in microphone 114 that receives sounds, the built-in speaker115 that outputs sounds, a sound input-output I/F 116 that processesinput and output of a sound signal between the microphone 114 and thespeaker 115 under the control of the CPU 101, a display I/F 117 thattransmits the image data to the display 120 externally mounted under thecontrol of the CPU 101, the external device connection I/F 118 thatconnects various external devices, the alarm lamp 119 that alarms theabnormalities of the various functions of the terminal 10, and a busline 110 that electrically connects the above-described components asillustrated in FIG. 5, such as an address bus or a data bus.

The display 120 is a display unit that includes a liquid crystal ororganic EL by which images of subjects and operation icons, for example,are displayed. The display 120 is connected to the display I/F 117 withthe cable 120 c. The cable 120 c may be an analog RGB (VGA) signalcable, a component video cable, a high-definition multimedia interface(HDMI) signal cable, or a digital video interactive (DVI) signal cable.

The camera 112 includes a lens and a solid state image capturing devicethat converts light into charges so as to generate an electricallyavailable image (picture) of a subject. As the solid state imagecapturing device, a complementary metal oxide semiconductor (CMOS) or acharge coupled device (CCD) is used, for example.

External devices such as an external camera, an external microphone, andan external speaker can be electrically connected to the external deviceconnection I/F 118 with universal serial bus (USB) cables inserted intothe connecting port 1132 of the housing 1100 illustrated in FIG. 6. Whenan external camera is connected, the external camera is driven prior tothe built-in camera 112 under the control of the CPU 101. Likewise, whenan external microphone and an external speaker are connected, theexternal microphone and the external speaker are driven prior to thebuilt-in microphone 114 and the built-in speaker 115 under the controlof the CPU 101.

The recording medium 106 is attached to the terminal 10 in a detachablemanner. An electrically erasable and programmable ROM (EEPROM) may beused, for example, as a non-volatile memory from which data is read orinto which data is written under the control of the CPU 101. Thenon-volatile memory is not limited to the flash memory 104.

FIG. 8 is a schematic diagram illustrating a hardware structure of themanagement system according to the embodiment. The management system 50includes a CPU 201 that controls the operation of the management system50, a ROM 202 that stores therein a program used to drive the CPU 201such as an IPL, a RAM 203 that is used as a working area of the CPU 201,an HD 204 that stores therein various types of data such as a programfor the management system 50, a hard disk drive (HDD) 205 that controlsreading of various types of data from or writing of various types ofdata into the HD 204 under control of the CPU 201, a media drive 207that controls reading data from or writing (storing) data into arecording medium 206 such as a flash memory, a display 208 that displaysvarious types of information such as a cursor, menus, windows,characters, or images, a network I/F 209 that performs datacommunication using the communication network 2, a keyboard 211 providedwith a plurality of keys to input characters, numerical values, andvarious instructions, a mouse 212 that is used to select and executevarious instructions, select items to be processed, and move the cursor,a CD-ROM drive 214 that controls reading of various types of data fromor writing of various types of data into a compact disc read only memory(CD-ROM) 213 as an example of an attachable-detachable recording medium,and a bus line 210 that electrically connects the above-describedcomponents as illustrated in FIG. 8, such as an address bus or a databus.

The relaying apparatus 30, the conversion system 80, the program supplysystem 90, and the maintenance system 100 have the same hardwarestructure as the management system 50. The description thereof is thusomitted. The respective HDs 204 store therein various types of programssuch as programs to control the respective ones of the relayingapparatus 30, the conversion system 80, the program supply system 90,and the maintenance system 100.

Each of the programs for the respective ones of the terminal 10, therelaying apparatus 30, the conversion system 80, the program supplysystem 90, and the maintenance system 100 may be recorded in acomputer-readable recording medium (e.g., the recording medium 106) as afile in an installable or executable format, and distributed. Examplesof the recording medium further include a compact disc recordable(CD-R), a digital versatile disk (DVD), and a blue-ray disk.

Functional Structure of Embodiment

A functional structure of the embodiment is described below. FIG. 9 is afunctional block diagram of the terminal 10, the relaying apparatus 30,the management system 50, and the conversion system 80 included in thetelephone conversation system 1 of the embodiment. In FIG. 9, theterminal 10, the relaying apparatus 30, the management system 50, andthe conversion system 80 are connected so as to enable datacommunication among them through the communication network 2.

Functional Structure of Terminal

The terminal 10 includes a transmitting-receiving unit 11, an operationinput reception unit 12, a login request unit 13, an image capturingunit 14, a sound input unit 15 a, a sound output unit 15 b, a displaycontrol unit 16, a delay detection unit 17, and a storage-readprocessing unit 19. The respective units are functions or operationsthat are achieved when any of the components illustrated in FIG. 7 areoperated by commands from the CPU 101 in accordance with the program forthe terminal 10 loaded on the RAM 103 from the flash memory 104. Theterminal 10 includes a storage unit 1000 structured by the RAM 103 andthe flash memory 104 that are illustrated in FIG. 7.

Functional Structures of Terminal

The following describes each functional structure of the terminal 10 indetail with reference to FIGS. 7 and 9. In the following description ofeach functional structure of the terminal 10, a relation between eachfunctional structure of the terminal 10 and related components thatachieve each functional structure of the terminal 10 in the componentsillustrated in FIG. 7 is also described.

The transmitting-receiving unit 11 of the terminal 10 illustrated inFIG. 9 is implemented by a command from the CPU 101 illustrated in FIG.7 and the network I/F 111 illustrated in FIG. 7. Thetransmitting-receiving unit 11 transmits and receives various types ofdata (or information) between itself and another terminal, apparatus, orsystem through the communication network 2. The transmitting-receivingunit 11 starts receiving state information indicating the state of eachterminals serving as a destination candidate from the management system50 before starting a telephone conversation with a desired destinationterminal. The state information indicates not only the operation stateof each terminal 10 (whether it is in an online state or an offlinestate) but also a detailed state such as, if it is in the online state,whether it is ready for making a telephone conversation, whether it isin a busy state, or whether a user is absent. In addition, the stateinformation indicates not only the operation state of the terminal 10but also various states in the terminal 10. For example, a state inwhich the cable 120 c is detached from the terminal 10, a state in whichthe terminal 10 outputs sounds but no images, and a state in which theterminal 10 outputs no sounds (MUTE). The following describes a casewhere the state information indicates the operation state, as anexample.

The operation input reception unit 12 is implemented by a command fromthe CPU 101 illustrated in FIG. 7, and the operation button 108 and thepower source switch 109 illustrated in FIG. 7. The operation inputreception unit 12 receives various types of input from a user. Forexample, when a user turns on the power source switch 109 illustrated inFIG. 7, the operation input reception unit 12 illustrated in FIG. 9receives the power source on operation and causes the power source to beturned on.

The login request unit 13 is implemented by a command from the CPU 101illustrated in FIG. 7. When receiving a power source on operation, thelogin request unit 13 automatically transmits login request informationindicating a request for a login and a current IP address of therequester terminal to the management system 50 from thetransmitting-receiving unit 11 through the communication network 2. Whenthe user switches the power source switch 109 from the on state to theoff state, the operation input reception unit 12 completely turns offthe power source after the transmitting-receiving unit 11 transmits thestate information indicating that the power source is to be turned offto the management system 50. As a result, the management system 50 cangrasp the fact that the power source of the terminal 10 has been turnedoff from the on state.

The image capturing unit 14 is implemented by a command from the CPU 101illustrated in FIG. 7 and the camera 112 and the image capturing deviceI/F 113 illustrated in FIG. 7. The image capturing unit 14 images asubject and outputs the resulting image data.

The sound input unit 15 a is implemented by a command from the CPU 101illustrated in FIG. 7 and the sound input-output I/F 116 illustrated inFIG. 7. After a sound of a user is converted into sound data by themicrophone 114, the sound input unit 15 a receives sound data relatingto the sound signal. The sound output unit 15 b is implemented by acommand from the CPU 101 illustrated in FIG. 7 and the soundinput-output I/F 116 illustrated in FIG. 7. The sound output unit 15 boutputs a sound signal relating to sound data to a speaker so as tocause the speaker 115 to output a sound.

The display control unit 16 is implemented by a command from the CPU 101illustrated in FIG. 7 and the display I/F 117 illustrated in FIG. 7. Asdescribed later, the display control unit 16 performs control so as tocombine the pieces of received image data having different resolutionsand transmit the combined image data to the display 120. The displaycontrol unit 16 can transmit information about a destination list, whichis received from the management system 50, to the display 120 so as tocause the display 120 to display the destination list.

The delay detection unit 17 is implemented by a command from the CPU 101illustrated in FIG. 7. The delay detection unit 17 detects a delay time(ms) of image data or sound data transmitted from another terminal 10through the relaying apparatus 30.

The storage-read processing unit 19 is executed by a command from theCPU 101 illustrated in FIG. 7 and the SSD 105 illustrated in FIG. 7 orimplemented by a command from the CPU 101. The storage-read processingunit 19 stores various types of data in the storage unit 1000 and readsvarious types of data from the storage unit 1000. The storage unit 1000stores therein a terminal identification (ID) and a password foridentifying the terminal 10, for example. In the storage unit 1000,image data and sound data that are received when a telephoneconversation is made with the destination terminal are stored andoverwritten with new image data and sound data at every receiving of thedata. In this regard, an image is displayed on the display 120 inaccordance with the image data before being overwritten while a sound isoutput from the speaker 115 in accordance with the sound data beforebeing overwritten.

The terminal ID and a relaying apparatus ID, which is described later,of the embodiment indicate identifying information used for uniquelyidentifying the terminal 10 and the relaying apparatus 30. For example,the identifying information is languages, characters, symbols, orvarious signs. The terminal ID and the relaying apparatus ID may be theidentifying information obtained by combining at least two of thelanguages, characters, symbols, and various signs.

Functional Structure of Relaying Apparatus

The relaying apparatus 30 includes a transmitting-receiving unit 31, astate detection unit 32, a data quality confirmation unit 33, a qualitychange management unit 34, a data quality change unit 35, and astorage-read processing unit 39. The respective units are functions oroperations that are implemented when any of the components illustratedin FIG. 8 are operated by commands from the CPU 201 in accordance withthe program for the relaying apparatus 30 loaded on the RAM 203 from theHD 204. The relaying apparatus 30 includes a storage unit 3000structured by the RAM 203 illustrated in FIG. 8 and/or the HD 204illustrated in FIG. 8.

Quality Change Management Table

FIG. 10 is a conceptual diagram illustrating a quality change managementtable. In the storage unit 3000, a quality change management database(DB) 3001 having the quality change management table illustrated in FIG.10 is structured. In the quality change management table, the IP addressof the terminal 10 serving as the relay destination (destination) ofimage data and image quality of the image data to be relayed by therelaying apparatus 30 to the relay destination are managed inassociation with each other.

Functional Structures of Relaying Apparatus

The following describes each functional structure of the relayingapparatus 30 in detail. In the following description of each functionalstructure of the relaying apparatus 30, a relation between eachfunctional structure of the relaying apparatus 30 and related componentsthat achieve each functional structure of the relaying apparatus 30among the components illustrated in FIG. 8 is also described.

The transmitting-receiving unit 31 of the relaying apparatus 30illustrated in FIG. 9 is implemented by a command from the CPU 201illustrated in FIG. 8 and the network I/F 209 illustrated in FIG. 8. Thetransmitting-receiving unit 31 transmits and receives various types ofdata (or information) between itself and another terminal, apparatus, orsystem through the communication network 2. The transmitting-receivingunit 31 initializes the communication session in the relaying apparatus30.

The transmitting-receiving unit 31 transmits session start instructioninformation that instructs a start of the communication session (thefirst communication session) to an address indicated with the IP addressof the requester terminal out of the IP addresses received by thetransmitting-receiving unit 31. The transmitting-receiving unit 31transmits the session start instruction information that instructs astart of the communication session (the second communication session)and the IP address of the destination terminal to an address indicatedwith the IP address of the conversion system 80 out of the IP addressesreceived by the transmitting-receiving unit 31.

The state detection unit 32 is implemented by a command from the CPU 201illustrated in FIG. 8. The state detection unit 32 detects the operationstate of the relaying apparatus 30 including the state detection unit32. The operation state is the “online” state, the “offline” state, the“busy” state, or a “temporary halt” state.

The data quality confirmation unit 33 is implemented by a command fromthe CPU 201 illustrated in FIG. 8. The data quality confirmation unit 33searches the quality change management table (refer to FIG. 10) usingthe IP address of the destination terminal as a searching key, andextracts the image quality of the image data to be relayed correspondingto the IP address, thereby confirming the image quality of the imagedata to be relayed.

The quality change management unit 34 is implemented by a command fromthe CPU 201 illustrated in FIG. 8. The quality change management unit 34changes the content of the quality change management table (refer toFIG. 10) in accordance with quality information, which is describedlater, transmitted from the management system 50. For example, in ateleconference held between the requester terminal (terminal 10 aa)having the terminal ID “01aa” and the destination terminal (terminal 10ba) having the terminal ID “10ba” by transmitting and receiving highimage quality image data, when a delay occurs in receiving the imagedata at the destination terminal (terminal 10 ba) due to a start ofanother teleconference held between the requester terminal (terminal 10bb) and the destination terminal (terminal 10 ca) through thecommunication network 2, the relaying apparatus 30 lowers the imagequality of the image data, which has been relayed by the relayingapparatus 30, from high image quality to medium image quality. In such acase, the content of the quality change management table (refer to FIG.10) is changed so as to lower the image quality of the image datarelayed by the relaying apparatus 30 from high image quality to mediumimage quality, in accordance with the quality information indicating themedium image quality.

The data quality change unit 35 is implemented by a command from the CPU201 illustrated in FIG. 8. The data quality change unit 35 changes theimage quality of the image data transmitted from the sender terminal inaccordance with the changed content of the quality change managementtable (refer to FIG. 10).

The storage-read processing unit 39 is implemented by a command from theCPU 201 illustrated in FIG. 8 and the HDD 205 illustrated in FIG. 8. Thestorage-read processing unit 39 stores various types of data in thestorage unit 3000 and reads various types of data stored in the storageunit 3000.

Functional Structure of Management System

The management system 50 includes a transmitting-receiving unit 51, aterminal authentication unit 52, a state management unit 53, adetermination unit 55, a session management unit 56, a qualitydetermination unit 57, a delay time management unit 58, and astorage-read processing unit 59. The respective units are functions oroperations that are implemented when any of the components illustratedin FIG. 8 are operated by commands from the CPU 201 in accordance withthe program for the management system 50 loaded on the RAM 203 from theHD 204. The management system 50 includes a storage unit 5000 structuredby the HD 204 illustrated in FIG. 8.

Relaying Apparatus Management Table

FIG. 11 is a conceptual diagram illustrating a relaying apparatusmanagement table. In the storage unit 5000, a relaying apparatusmanagement DB 5001 having the relaying apparatus management tableillustrated in FIG. 11 is structured. In the relaying apparatusmanagement table, the operation state of the relaying apparatus 30, areceiving date at which the management system 50 receives the stateinformation indicating the operation state, the IP address of therelaying apparatus 30, and a maximum data speed in telephoneconversation (Mbps) of the relaying apparatus 30 are managed inassociation with each other for each relaying apparatus ID of therelaying apparatuses 30. For example, the relaying apparatus managementtable illustrated in FIG. 11 indicates that, in relation to the relayingapparatus 30 a having the relaying apparatus ID “111a”, the operationstate is “online”, the date at which the management system 50 receivesthe state information is “13:00 on Nov. 10, 2011”, the IP address is“1.2.1.2”, and the maximum data speed in telephone conversation is 100Mbps.

Terminal Information Management Table

FIG. 12 is a conceptual diagram illustrating a terminal informationmanagement table. In the storage unit 5000, a terminal informationmanagement DB 5002 having the terminal information management tableillustrated in FIG. 12 is structured. In the terminal informationmanagement table, a password for identification, a model number of theterminal 10, a serial number of the terminal 10, a communication schemeof the terminal 10, and the IP address of the non-dedicated terminal Din association with each other for each terminal ID of all of theterminals 10 managed by the management system 50. For example, theterminal information management table illustrated in FIG. 12 indicatesthat, in relation to the terminal 10 da, the terminal ID is “01da”, thepassword is “dada”, the model number is “8001”, the serial number is“1001”, the communication scheme is “non-dedicated 1”, and the IPaddress is “1.3.2.3”. The IP addresses of the non-dedicated terminals Dare managed as static data in the terminal information management table(refer to FIG. 12) whereas the IP addresses of the dedicated terminals Aare managed as dynamic data in a terminal state management tabledescribed below (refer to FIG. 13). Thus, the dedicated terminal A ismore convenient than the non-dedicated terminal D in terms of that thededicated terminal A copes with a change in IP address.

In the terminal information management table, “dedicated” in thecommunication scheme represents the communication scheme that thededicated terminal A, which is illustrated in FIGS. 2 and 4, uses. Thecommunication scheme of “non-dedicated 1” represents the communicationscheme that the non-dedicated terminal D illustrated in FIG. 4 uses. Thecommunication scheme of “non-dedicated 2” represents a communicationscheme that is different from the communication schemes that thededicated terminal A and the non-dedicated terminal D use.

Terminal State Management Table

FIG. 13 is a conceptual diagram illustrating a terminal state managementtable. In the storage unit 5000, a terminal state management DB 5003having the terminal state management table illustrated in FIG. 13 isstructured. In the terminal state management table, for each terminal IDof the terminals 10, the terminal name of the terminal 10 whendesignated as the destination, the operation state of the terminal 10, areceiving date at which the management system 50 receives the loginrequest information, which is described later, and the IP address of theterminal 10 are managed in association with each other. For example, theterminal state management table illustrated in FIG. 13 indicates that,in relation to the terminal 10 aa having the terminal ID “01aa”, theterminal name is “terminal AA, Tokyo business office, Japan”, theoperation state is “online (ready for making a telephone conversation)”,the date at which management system 50 receives the login requestinformation is “13:40 on Nov. 10, 2011”, and the IP address is“1.2.1.3”.

The terminal state management table does not manage the IP addresses ofthe terminals 10 other than the dedicated terminals A, i.e., thenon-dedicated terminals D, because the non-dedicated terminals D are notincluded therein as management targets.

Destination List Management Table

FIG. 14 is a conceptual diagram illustrating a destination listmanagement table. In the storage unit 5000, a destination listmanagement DB 5004 having the destination list management tableillustrated in FIG. 14 is structured. In the destination list managementtable, the terminal ID of the requester terminal that requests a startof a telephone conversation is associated with all of terminal IDs ofthe destination terminals registered as the destination candidates ofthe requester terminal. For example, the destination list managementtable illustrated in FIG. 14 indicates that the destination candidatesof the requester terminal (terminal 10 aa) having the terminal ID “01aa”are the terminal 10 ab having the terminal ID “01ab”, the terminal 10 bahaving the terminal ID “01ba”, and the terminal 10 bb having theterminal ID “01bb”. The requester terminal (terminal 10 aa) can requesta start of a telephone conversation to those destination candidates.Update of the destination candidates is performed by adding or deletinga terminal in accordance with an adding request or a deleting requestmade from an arbitrary requester terminal to the management system 50.In contrast to the destination list management table (refer to FIG. 14)that does not manage the terminal IDs of the terminals 10 other than thededicated terminals A, the terminal state management table (refer toFIG. 13) manages terminal IDs of the terminals 10 other than thededicated terminals A.

Session Management Table

FIG. 15 is a conceptual diagram illustrating a session management table.In the storage unit 5000, a session management DB 5005 having thesession management table illustrated in FIG. 15 is structured. In thesession management table, a session ID, the relaying apparatus ID of therelaying apparatus 30 used for relaying image data and sound data, theterminal ID of the requester terminal, the terminal ID of thedestination terminal, delay time (ms) in receiving the image data at thedestination terminal, and the receiving date at which the managementsystem 50 receives delay time information indicating the delay time fromthe destination terminal are managed in association with each other. Forexample, the session management table illustrated in FIG. 15 indicatesthat the relaying apparatus 30 a (the relaying apparatus ID is “111a”)relays image data and sound data between the requester terminal(terminal 10 aa) having the terminal ID “01aa” and the destinationterminal (terminal 10 ca) having the terminal ID “01ca”, and the delaytime of the image data is 200 (ms) at the destination terminal (terminal10 ca) as at “14:00 on Nov. 10, 2011”. When a telephone conversation ismade between two terminals 10, the receiving date of the delay timeinformation may be managed in accordance with the delay time informationtransmitted from the requester terminal, instead of the destinationterminal. However, when a telephone conversation is made among three ormore terminals 10, the receiving date of the delay time information ismanaged in accordance with the delay time information transmitted fromthe terminal 10 that receives image data and sound data.

Conversion Management Table

FIG. 16 is a conceptual diagram illustrating a conversion managementtable. In the storage unit 5000, a conversion management DB 5006 havingthe conversion management table illustrated in FIG. 16 is structured. Inthe conversion management table, the terminal ID of the non-dedicatedterminal (including the terminals using the non-dedicated 1 and thenon-dedicated 2 as the communication schemes), the IP address of theconversion system 80, and the IP address of the non-dedicated terminalare managed in association with each other.

Quality Management Table

FIG. 17 is a conceptual diagram illustrating a quality management table.In the storage unit 5000, a quality management DB 5007 having thequality management table illustrated in FIG. 17 is structured. In thequality management table, the delay time information indicating thedelay time of image data and image quality information indicating imagequality (quality of an image) of image data are managed in associationwith each other in such a manner that as the delay time (ms) of imagedata at the requester terminal or the destination terminal increases,the image quality of image data relayed by the relaying apparatus 30 islowered.

Functional Structures of Management System

The following describes each functional structure of the managementsystem 50 in detail. In the following description of each functionalstructure of the management system 50, a relation between eachfunctional structure of the management system 50 and related componentsthat achieve each functional structure of the management system 50 amongthe components illustrated in FIG. 8 is also described.

The transmitting-receiving unit 51 is executed by a command from the CPU201 illustrated in FIG. 8 and the network I/F 209 illustrated in FIG. 8.The transmitting-receiving unit 51 transmits and receives various typesof data (or information) between itself and the other terminals,apparatuses, or the system through the communication network 2.

The terminal authentication unit 52 is implemented by a command from theCPU 201 illustrated in FIG. 8. The terminal authentication unit 52searches the terminal information management table (refer to FIG. 12)using the terminal ID and the password that are included in the loginrequest information received through the transmitting-receiving unit 51as searching keys, and performs terminal authentication by determiningwhether the same terminal ID and password are managed in the terminalinformation management table.

The state management unit 53 is implemented by a command from the CPU201 illustrated in FIG. 8. The state management unit 53 stores theterminal ID of the requester terminal, the operation state of therequester terminal, the receiving date at which the management system 50receives the login request information, and the IP address of therequester terminal in the terminal state management table (refer to FIG.13) and manages them in association with each other so as to manage theoperation state of the requester terminal that makes a login request.The state management unit 53 changes the operation state in the terminalstate management table (refer to FIG. 13) from online to offline inaccordance with the state information that is sent from the terminal 10and indicates that the power source is to be turned off when a userturns off the power source switch 109 of the terminal 10 from the onstate.

The determination unit 55 is implemented by a command from the CPU 201illustrated in FIG. 8. The determination unit 55 determines whether thecommunication scheme used by the terminal 10 is the communication schemeused by the dedicated terminal A.

The session management unit 56 is implemented by a command from the CPU201 illustrated in FIG. 8. The session management unit 56 stores, in thesession management table of the storage unit 5000 (refer to FIG. 15),the relaying apparatus ID of the relaying apparatus 30 used for relayingtelephone conversation data, the terminal ID of the requester terminal,the terminal ID of the destination terminal, the delay time (ms) inreceiving image data at the destination terminal, and the receiving dateat which the management system 50 receives the delay time informationindicating the delay time from the destination terminal in associationwith each other, and manages them. The session management unit 56produces the session ID used for establishing the communication session.

The quality determination unit 57 determines the image quality of imagedata relayed by the relaying apparatus 30 on the basis of the imagequality information about the image data extracted by the storage-readprocessing unit 59, which is described later.

The delay time management unit 58 is implemented by a command from theCPU 201 illustrated in FIG. 8. The delay time management unit 58 stores,in the session management table of the session management DB 5005 (referto FIG. 15), the delay time indicated by the delay time information in afield of the delay time of a record including the terminal ID extractedby the storage-read processing unit 59, which is described later.

The storage-read processing unit 59 is executed by a command from theCPU 201 illustrated in FIG. 8 and the HDD 205 illustrated in FIG. 8. Thestorage-read processing unit 59 stores various types of data in thestorage unit 5000 and reads various types of data stored in the storageunit 5000. For example, the storage-read processing unit 59 searches therespective management DBs structured in the storage unit 5000 and readsdata (information) corresponding to a searching key as a searchingresult.

Functional Structure of Conversion System

The conversion system 80 includes a transmitting-receiving unit 81, acommunication scheme conversion unit 82, and a storage-read processingunit 89. The respective units are functions or operations that areimplemented when any of the components illustrated in FIG. 8 areoperated by commands from the CPU 201 in accordance with the program forthe conversion system 80 loaded on the RAM 203 from the HD 204. Theconversion system 80 includes a storage unit 8000 structured by the RAM203 illustrated in FIG. 8 and/or the HD 204 illustrated in FIG. 8. Thestorage unit 8000 stores therein conversion rule data used for theconversion of communication data.

Functional Structures of Conversion System

The following describes each functional structure of the conversionsystem 80 in detail with reference to FIGS. 8 and 9. In the followingdescription of each functional structure of the conversion system 80, arelation between each functional structure of the conversion system 80and related components that achieve each functional structure of theconversion system 80 among the components illustrated in FIG. 8 is alsodescribed.

The transmitting-receiving unit 81 of the conversion system 80illustrated in FIG. 9 is implemented by a command from the CPU 201illustrated in FIG. 8 and the network I/F 209 illustrated in FIG. 8. Thetransmitting-receiving unit 81 transmits and receives various types ofdata (or information) between itself and another terminal, apparatus, orsystem through the communication network 2. The transmitting-receivingunit 81 transmits session start instruction information to instruct astart of the communication session (the third communication session) tothe destination indicated by position information transmitted by therelaying apparatus 30. Examples of the position information include theIP address and a uniform resource identifier (URI).

The communication scheme conversion unit 82 mutually converts thecommunication scheme of the telephone conversation data transmitted fromthe requester terminal and the communication scheme of the telephoneconversation data transmitted from the destination terminal inaccordance with the conversion rule data of the communication schemestored in the storage unit 8000.

The storage-read processing unit 89 is executed by a command from theCPU 201 illustrated in FIG. 8 and the HDD 205 illustrated in FIG. 8. Thestorage-read processing unit 89 stores various types of data in thestorage unit 8000 or reads various types of data stored in the storageunit 8000.

Processing or Operation of Embodiment

The following describes the first communication pattern in which atelephone conversation is made between two dedicated terminals A withreference to FIGS. 18 to 25C. Specifically, a case is described where atelephone conversation is made between the terminal 10 aa serving as thededicated terminal A and the terminal 10 ca serving as the dedicatedterminal A. FIG. 18 is a sequence diagram illustrating processing at apreparatory stage in which a preparation is made for starting atelephone conversation between the terminals. In FIG. 18, various typesof management information are all transmitted and received by themanagement communication session sei illustrated in FIG. 2.

When a user turns on the power source switch 109 illustrated in FIGS. 6and 7, the operation input reception unit 12 illustrated in FIG. 9receives the power source on operation and causes the power source to beturned on as illustrated in FIG. 18 (step S21). When the power source onoperation is received, the login request unit 13 automatically transmitsthe login request information indicating a request for a login to themanagement system 50 from the transmitting-receiving unit 11 through thecommunication network 2 (step S22). The login request informationincludes the terminal ID and the password with which the terminal canidentify itself serving as the requester terminal (the transmissionterminal 10 aa). The terminal ID and the password are read from thestorage unit 1000 through the storage-read processing unit 19 andtransmitted to the transmitting-receiving unit 11 as data. When thelogin request information is transmitted to the management system 50from the requester terminal (terminal 10 aa), the management system 50serving as the receiving side can grasp the IP address of the requesterterminal (terminal 10 aa) serving as the transmission side.

The terminal authentication unit 52 of the management system 50 searchesthe terminal information management table (refer to FIG. 12) using theterminal ID and the password that are included in the login requestinformation received through the transmitting-receiving unit 51 assearching keys, and performs terminal authentication by determiningwhether the same terminal ID and password are managed in the terminalinformation management DB 5002 (step S23). If the terminalauthentication unit 52, which manages the same terminal ID and password,determines that the login request is transmitted from the authenticterminal 10 having a use authority, the state management unit 53 stores,in the terminal state management table (refer to FIG. 13), the terminalID and the operation state of the requester terminal (terminal 10 aa),the receiving date of the login request information, and the IP addressof the terminal 10 aa in association with each other (step S24). As aresult, the terminal state management table (refer to FIG. 13) managesthe operation state “online”, the receiving date “13:40 on Nov. 10,2011”, and the IP address “1.2.1.3” of the requester terminal (terminal10 aa) in association with the terminal ID “01aa”.

The transmitting-receiving unit 51 of the management system 50 transmitsauthentication result information indicating the authentication resultobtained by the terminal authentication unit 52 to the requesterterminal (terminal 10 aa) that has made the login request through thecommunication network 2 (step S25). In the embodiment, the followingdescription is made on the case where the requester terminal isdetermined as the authentic terminal 10 having a use authority by theterminal authentication unit 52.

The storage-read processing unit 59 of the management system 50 searchesthe destination list management table (refer to FIG. 14) using theterminal ID “01aa” of the requester terminal (terminal 10 aa) that hasmade the login request as a searching key, and extracts the terminal IDsof the candidates of the destination terminal capable of performingcommunication with the requester terminal (terminal 10 aa) (step S26).In this case, the terminal IDs (“01ab”, “01ba”, etc.) of the destinationterminals (terminals 10 ab, 10 ba, etc.) corresponding to the terminalID “01aa” of the requester terminal (terminal 10 aa) are extracted.

The storage-read processing unit 59 searches the terminal statemanagement table (refer to FIG. 13) using the terminal IDs (“01ab”,“01ba”, etc.) of the candidates of the destination terminal extracted atstep S26 as searching keys, reads the operation states (“offline”,“online”, etc.) corresponding to the respective terminal IDs, andacquires the respective operation states of the terminals (10 ab, 10 ba,etc.) (step S27).

The transmitting-receiving unit 51 transmits, to the requester terminal(terminal 10 aa) through the communication network 2, destination stateinformation including the terminal IDs (“01ab”, “01ba”, etc.) used asthe searching keys at step S27 and the respective operation states(“offline”, “online”, etc.) of the destination terminals (terminals 10ab, 10 ba, etc.) corresponding to the respective terminal IDs (stepS28). As a result, the requester terminal (terminal 10 aa) can grasp therespective current operation states (“offline”, “online”, etc.) of theterminals (10 ab, 10 ba, etc.) that are the candidates of thedestination terminal capable of performing communication with therequester terminal (terminal 10 aa).

The storage-read processing unit 59 searches the destination listmanagement table (refer to FIG. 14) using the terminal ID “01aa” of therequester terminal (terminal 10 aa) that has made the login request as asearching key, and extracts the terminal IDs of other requesterterminals that register the terminal ID “01aa” of the requester terminal(terminal 10 aa) as the candidate of the destination terminal (stepS29). In the destination list management table illustrated in FIG. 14,the terminal IDs “01ba”, “01ca”, and “01da” are extracted as those ofthe other requester terminals, for example. In the followingdescription, the terminal IDs “01ba”, “01ca”, and “01da” are extractedas those of the other requester terminals, for simple explanation.

The storage-read processing unit 59 searches the terminal statemanagement table (refer to FIG. 13) using the terminal ID “01aa” of therequester terminal (terminal 10 aa) that has made the login request as asearching key, and acquires the operation state of the requesterterminal (terminal 10 aa) that has made the login request (step S30).The transmitting-receiving unit 51 transmits the destination stateinformation including the terminal ID “01aa” of the requester terminal(terminal 10 aa) and the operation state “online” that are acquired atstep S30 to the terminals (10 ba and 10 ca) each operation state ofwhich is “online” in the terminal state management table (refer to FIG.13) in the terminals (10 ba, 10 ca, and 10 da) that are identified withthe terminal IDs (“01ba”, “01ca”, and “01da”) extracted at step S29(steps S31-1 and S31-2). When transmitting the destination stateinformation to the terminals (10 ba and 10 ca), thetransmitting-receiving unit 51 refers to the IP addresses of theterminals managed by the terminal state management table (refer to FIG.13) in accordance with the respective terminal IDs (“01ba” and “01ca”).As a result, the terminal ID “01aa” and the operation state “online” ofthe requester terminal (terminal 10 aa) that has made the login requestcan be transmitted to each of the other destination terminals (terminals10 ba and 10 ca) capable of performing communication with the requesterterminal (terminal 10 aa) that has made the login request as thedestination.

The transmitting-receiving unit 51, however, cannot transmit, to theterminal 10 da serving as the non-dedicated terminal D, the terminal ID“01aa” and the operation state “online” of the requester terminal(terminal 10 aa) that has made the login request because the operationstate of the non-dedicated terminal D is not managed by the terminalstate management table (refer to FIG. 13). The non-dedicated terminal Dcannot enjoy services and cannot receive the operation state of thededicated terminal A.

In each of the other terminals 10, when a user turns on the power sourceswitch 109 illustrated in FIGS. 6 and 7, the operation input receptionunit 12 illustrated in FIG. 9 receives the power source on operation inthe same manner as step S21, and then the processing is performed in thesame manner as steps S22 to S31-1 and S31-2. The description thereof isthus omitted.

The following describes the case where a telephone conversation is madebetween two dedicated terminals A with reference to FIGS. 6, 9, and 19to 22. FIG. 19 is a sequence diagram illustrating a request for statinga telephone conversation.

As illustrated in FIG. 19, when a user of the requester terminal(terminal 10 aa) serving as the dedicated terminal A presses down theoperation button 108 illustrated in FIG. 6 to select the destinationterminal (terminal 10 ca) that is a destination candidate and serves asthe dedicated terminal A, the operation input reception unit 12illustrated in FIG. 9 receives the request for starting a telephoneconversation with the destination terminal (terminal 10 ca) (step S41).The transmitting-receiving unit 11 of the requester terminal (terminal10 aa) transmits, to the management system 50, start request informationindicating the start of the telephone conversation (step S42). The startrequest information includes the terminal ID “01aa” of the requesterterminal (terminal 10 aa) and the terminal ID “01ca” of the destinationterminal (terminal 10 ca).

The state management unit 53 of the management system 50 illustrated inFIG. 9 changes both fields of the operation state in the recordsincluding the respective terminal IDs “01aa” and “01ca” of the terminalstate management table (refer to FIG. 13) to “online (busy)” inaccordance with the terminal ID “01aa” of the requester terminal(terminal 10 aa) and the terminal ID “01ca” of the destination terminal(terminal 10 ca) that are included in the start request information(step S43). The requester terminal (terminal 10 aa) and the destinationterminal (terminal 10 ca) do not start a telephone conversation,actually; however, their states are changed to “busy”. If anotherterminal 10 tries to have a telephone conversation with the requesterterminal (terminal 10 aa) or the destination terminal (terminal 10 ca),a notification sound or display that indicates what is called a busyline is output.

The session management unit 56 of the management system 50 produces thesession ID used for establishing the communication session (step S44).The management system 50 determines which communication scheme is usedby the destination terminal (terminal 10 ca) (step S45).

The processing performed at step S45 is described in further detailbelow with reference to FIG. 20. FIG. 20 is a flowchart illustrating thedetermination on the communication scheme.

As illustrated in FIG. 20, the storage-read processing unit 59 searchesthe terminal information management table (refer to FIG. 12) on thebasis of the terminal ID “01ca” of the destination terminal (terminal 10ca) received by the transmitting-receiving unit 51, and extracts thecommunication scheme information corresponding to the terminal ID “01ca”(step S45-1).

The determination unit 55 determines whether the communication schemeindicated by the extracted communication scheme information is thecommunication scheme used by the requester terminal (terminal 10 aa)serving as the dedicated terminal A (step S45-2). Specifically, thedetermination unit 55 determines whether the communication schemeindicated by the communication scheme information extracted by thestorage-read processing unit 59 is the same as the communication schemeused by the requester terminal (terminal 10 aa). In the case that thecommunication schemes are the same, both of the call control scheme andthe coding scheme are the same whereas in the case that thecommunication schemes are not the same (different from each other), atleast one of the call control scheme and the coding scheme differs fromeach other.

If the determination unit 55 determines that the communication schemesare the same (Yes at step S45-2), the processing proceeds to step S61illustrated in FIG. 21, which is described later. In this case, thedestination terminal (terminal 10 ca) is the dedicated terminal A, whichis the same type as the requester terminal (terminal 10 aa), and thusthe following description is made from step S61. FIG. 21 is a sequencediagram illustrating processing to establish the communication sessionbefore the telephone conversation is made between two dedicatedterminals A. In the embodiment, a case is described where the relayingapparatus 30 a connected to the LAN 2 a, to which the requester terminal(terminal 10 aa) is connected, is used in the relaying apparatuses 30.

As illustrated in FIG. 21, the management system 50 transmits, to therelaying apparatus 30 a from the transmitting-receiving unit 51, sessioninitialization request information to initialize the communicationsession established by the relaying apparatus 30 a (step S61). Thesession initialization request information includes the session IDproduced at step S44, the respective IP addresses of the requesterterminal (terminal 10 aa) and the destination terminal (terminal 10 ca)that are managed by the terminal state management table (refer to FIG.13). When transmitting the session initialization request information tothe relaying apparatus 30 a, the management system 50 transmits also theIP address of the management system 50. As a result, thetransmitting-receiving unit 31 of the relaying apparatus 30 a receivesthe session initialization request information and the IP address of themanagement system 50.

The transmitting-receiving unit 31 of the relaying apparatus 30 ainitializes the communication session (step S62). Thetransmitting-receiving unit 31 transmits, to the requester terminal(terminal 10 aa), the session start instruction information indicatingthe instruction to start the communication session (step S63). Thesession start instruction information includes the session IDtransmitted from the management system 50. When transmitting the sessionstart instruction information to the requester terminal (terminal 10aa), the relaying apparatus 30 a transmits also the IP address of therelaying apparatus 30 a. As a result, the transmitting-receiving unit 11of the requester terminal (terminal 10 aa) receives the session startinstruction information and the IP address of the relaying apparatus 30a.

In the same manner, the transmitting-receiving unit 31 transmits, to thedestination terminal (terminal 10 ca), the session start instructioninformation indicating the instruction to start the communicationsession (step S64). The session start instruction information includesthe session ID transmitted from the management system 50. Whentransmitting the session start instruction information to thedestination terminal (terminal 10 ca), the relaying apparatus 30 atransmits also the IP address of the relaying apparatus 30 a. As aresult, the transmitting-receiving unit 11 of the destination terminal(terminal 10 ca) receives the session start instruction information andthe IP address of the relaying apparatus 30 a.

As a result of the processing at step S63, the communication session(the first communication session sed1 illustrated in FIG. 2) to transmitand receive telephone conversation data is established between therequester terminal (terminal 10 aa) and the relaying apparatus 30 a(step S65-1). As a result of the processing at step S64, thecommunication session (the second communication session sed2 illustratedin FIG. 2) to transmit and receive telephone conversation data isestablished between the relaying apparatus 30 a and the destinationterminal (terminal 10 ca) (step S65-2).

The following describes processing to transmit and receive telephoneconversation data for a telephone conversation such as a teleconferencebetween the requester terminal and the destination terminal withreference to FIG. 22. FIG. 22 is a sequence diagram illustratingprocessing in which telephone conversation data is transmitted andreceived between the two dedicated terminals A. The transmitting andreceiving the telephone conversation data and detection of the delaytime, which is described later, are processed in the same manner both inthe processing for transmitting the telephone conversation data from theterminal 10 aa to the terminal 10 ca in one direction and in theprocessing for transmitting the telephone conversation data from theterminal 10 ca to the terminal 10 a in the opposite direction. Thus, thecommunication in the one direction is described while the description ofthe communication in the opposite direction is omitted.

The requester terminal (terminal 10 aa) transmits image data of asubject imaged by the image capturing unit 14, and sound data of a soundreceived by the sound input unit 15 a to the relaying apparatus 30 afrom the transmitting-receiving unit 11 through the communicationnetwork 2 using the communication session sed1 (step S81). In theembodiment, high image quality image data composed of three pieces ofimage data of low resolution, medium resolution, and high resolutionillustrated in FIG. 3 and sound data are transmitted. As a result, inthe relaying apparatus 30 a, the transmitting-receiving unit 31 receivesthe image data composed of three pieces of different resolution imagedata and the sound data. The data quality confirmation unit 33 searchesthe quality change management table (refer to FIG. 10) using the IPaddress “1.3.1.3” of the destination terminal (terminal 10 ca) as asearching key, extracts the image quality, which corresponds to the IPaddress, of the image data to be relayed, and confirms the image qualityof the image data to be relayed (step S82). In the embodiment, theconfirmed image quality of the image data is “high image quality”, whichis the same as that of the image data received by thetransmitting-receiving unit 31. Thus, the relaying apparatus 30 atransmits the image data and the sound data to the destination terminal(terminal 10 ca) without any change in quality using the communicationsession sed2 (step S83). As a result, the transmitting-receiving unit 11of the destination terminal (terminal 10 ca) receives the high imagequality image data composed of three pieces of image data of lowresolution, medium resolution, and high resolution, and the sound data.The display control unit 16 can combine the three pieces of image datahaving different resolutions, causing the display 120 to display theresulting image and causing the sound output unit 15 b to output a soundbased on the sound data.

The delay detection unit 17 of the destination terminal (terminal 10 ca)detects the delay time in receiving of image data received by thetransmitting-receiving unit 11 at a regular time intervals (e.g., everyone second) (step S84). In the embodiment, the following description ismade on a case where the delay time is 200 (ms).

The transmitting-receiving unit 11 of the destination terminal (terminal10 ca) transmits the delay time information indicating the delay time“200 (ms)” to the management system 50 through the communication network2 using the management communication session sei illustrated in FIG. 2(step S85). As a result, the management system 50 can grasp the delaytime and the IP address “1.3.1.3” of the terminal 10 ca serving as thesender of the delay time information.

The delay time management unit 58 of the management system 50 searchesthe terminal state management table (refer to FIG. 13) using the IPaddress “1.3.1.3” of the destination terminal (terminal 10 ca) as asearching key, and extracts the terminal ID “01ca” corresponding to theIP address. In addition, the delay time management unit 58 stores thedelay time “200 (ms)” indicated by the delay time information in thefield of the delay time of the record of the terminal ID “01ca” in thesession management table (refer to FIG. 15) and manages it (step S86).

The quality determination unit 57 searches the quality management table(refer to FIG. 17) using the delay time “200 (ms)” as a searching key,extracts the image quality “medium image quality” of the image datacorresponding to the delay time, and determines the image quality as the“medium image quality” (step S87).

The transmitting-receiving unit 51 searches the relaying apparatusmanagement table (refer to FIG. 11) using the relaying apparatus ID“111a” associated with the terminal ID “01ca” in the session managementtable (refer to FIG. 15) as a searching key, and extracts the IP address“1.2.1.2” of the relaying apparatus 30 a corresponding to the relayingapparatus ID (step S88). The transmitting-receiving unit 51 transmitsthe quality information indicating the image quality “medium imagequality” of the image data determined at step S87 to the relayingapparatus 30 a through the communication network 2 using the managementcommunication session sei (step S89). The quality information includesthe IP address “1.3.1.3” of the destination terminal (terminal 10 ca)used as the searching key at step S86. As a result, the quality changemanagement unit 34 of the relaying apparatus 30 a stores, in the qualitychange management table (refer to FIG. 10), the IP address “1.3.1.3” ofthe terminal 10 serving as the transmission destination (in this case,the terminal 10 ca) and the image quality “medium image quality” of theimage data to be relayed in association with each other, and managesthem (step S90).

The requester terminal (terminal 10 aa) transmits the high image qualityimage data composed of three pieces of image data of low resolution,medium resolution, and high resolution and the sound data to therelaying apparatus 30 a using the first communication session sed1 inthe same manner as step S81 (step S91). As a result, the data qualityconfirmation unit 33 of the relaying apparatus 30 searches the qualitychange management table (refer to FIG. 10) using the IP address“1.3.1.3” of the destination terminal (terminal 10 ca) as a searchingkey, extracts the image quality “medium image quality”, whichcorresponds to the IP address, of the image data to be relayed, andconfirms the image quality of the image data to be relayed in the samemanner as step S82 (step S92). In the embodiment, the confirmed imagequality of the image data is “medium image quality”, which is lower thanthe image quality “high image quality” of the image data received by thetransmitting-receiving unit 31. Thus, the data quality change unit 35changes the image quality of the image data by decreasing the level ofthe image quality of the image data from “high image quality” to “mediumimage quality” (step S93).

The transmitting-receiving unit 31 transmits the image data the imagequality of which has been changed to “medium image quality” and thesound data the sound quality of which has not been changed to thedestination terminal (terminal 10 ca) through the communication network2 using the second communication session sed2 (step S94). As a result,the transmitting-receiving unit 11 of the destination terminal (terminal10 ca) receives the medium image quality image data composed of twopieces of image data of low resolution and medium resolution, and thesound data. The display control unit 16 can combine the two pieces ofimage data having different resolutions, causing the display 120 ca todisplay the resulting image and causing the sound output unit 15 b tooutput a sound based on the sound data.

In this way, when delay in receiving occurs at the destination terminal(terminal 10 ca) that receives image data, the relaying apparatus 30 achanges the image quality such that the users participating in thetelephone conversation, such as a teleconference, do not feeluncomfortable with the image. The two dedicated terminals A can enjoyservices for coping with the delay in receiving of image data.

The following describe the second communication pattern in which atelephone conversation is made between the dedicated terminal A (anexample of the first communication terminal) and the non-dedicatedterminal D (an example of the second communication terminal) withreference to FIGS. 20, 23, 24, and 25A to 25C. Specifically, a telephoneconversation is made between the terminal 10 aa serving as the dedicatedterminal A and the terminal 10 da serving as the non-dedicated terminalD. In the embodiment, the description is made on the following case. Inthe communication scheme used by the terminal 10 aa, the call controlscheme is the protocol of the instant messenger (or the extended versionof the protocol of the instant messenger) and the coding scheme is SVC.In the communication scheme used by the terminal 10 da, the call controlscheme is SIP and the coding scheme is AVC.

In the second communication pattern, the selection of the destination atstep S41 differs from the first communication pattern in that theterminal 10 da is selected as the destination terminal instead of theterminal 10 ca, and the terminal ID used for transmission, receiving andsearching in accordance with the change only differs from that in thefirst communication pattern. The description thereof is thus omitted.The following description is made on a case where the determination unit55 determines that the communication schemes are not the same (differfrom each other), i.e., No at step S45-2 illustrated in FIG. 20.

In the second communication pattern, the storage-read processing unit 59searches the conversion management table (refer to FIG. 16) on the basisof the terminal ID “01da” of the destination terminal (terminal 10 da)received by the transmitting-receiving unit 51, and extracts the IPaddress “1.3.2.2” of the conversion system 80 and the IP address“1.3.2.3” of the destination terminal (terminal 10 da) that correspondto the terminal ID “01da” (step S45-3). The processing then proceeds tostep S101 illustrated in FIG. 23, which is described below.

FIG. 23 is a sequence diagram illustrating processing to establish thecommunication session before a telephone conversation is made betweenthe dedicated terminal A and the non-dedicated terminal D. Asillustrated in FIG. 23, the management system 50 transmits, to therelaying apparatus 30 a from the transmitting-receiving unit 51, thesession initialization request information to initialize thecommunication session established by the relaying apparatus 30 a (stepS101). The session initialization request information includes thesession ID and the respective IP addresses of the requester terminal(terminal 10 aa), the conversion system 80, and the destination terminal(terminal 10 da). The session ID is produced at step S44. The IP addressof the requester terminal (terminal 10 aa) is managed by the terminalstate management table (refer to FIG. 13). The respective IP addressesof the conversion system 80 and the destination terminal (terminal 10da) are extracted at step S45-3.

When transmitting the session initialization request information to therelaying apparatus 30 a, the management system 50 transmits also the IPaddress of the management system 50. As a result, thetransmitting-receiving unit 31 of the relaying apparatus 30 a receivesthe session initialization request information and the IP address of themanagement system 50.

The transmitting-receiving unit 31 of the relaying apparatus 30 ainitializes the communication session (step S102). Thetransmitting-receiving unit 31 transmits, to the requester terminal(terminal 10 aa), the session start instruction information indicatingthe instruction to start the communication session (step S103). Thesession start instruction information includes the session IDtransmitted from the management system 50. When transmitting the sessionstart instruction information to the requester terminal (terminal 10aa), the relaying apparatus 30 a transmits also the IP address of therelaying apparatus 30 a. As a result, the transmitting-receiving unit 11of the requester terminal (terminal 10 aa) receives the session startinstruction information and the IP address of the relaying apparatus 30a.

In the same manner, the transmitting-receiving unit 31 transmits, to theconversion system 80, the session start instruction informationindicating the instruction to start the communication session (stepS104). The session start instruction information includes the session IDand the IP address of the destination terminal (terminal 10 da) that aretransmitted from the management system 50. The transmitting-receivingunit 31 thus transmits the session start instruction information and theIP address of the destination terminal (terminal 10 da). Whentransmitting the session start instruction information to the conversionsystem 80, the relaying apparatus 30 a transmits also the IP address ofthe relaying apparatus 30 a. As a result, the transmitting-receivingunit 81 of the conversion system 80 receives the session startinstruction information and the IP address of the relaying apparatus 30a.

In the second communication pattern, the transmitting-receiving unit 81of the conversion system 80 transmits, to the destination terminal(terminal 10 da), the session start instruction information indicatingthe instruction to start the communication session (step S105). Thesession start instruction information includes the session IDtransmitted from the management system 50. When transmitting the sessionstart instruction information to the destination terminal (terminal 10da), the conversion system 80 transmits also the IP address of theconversion system 80. As a result, the transmitting-receiving unit 11 ofthe destination terminal (terminal 10 da) receives the session startinstruction information and the IP address of the conversion system 80.

As a result of the processing at step S103, the communication session(the first communication session sed11 illustrated in FIG. 4) totransmit and receive telephone conversation data is established betweenthe requester terminal (terminal 10 aa) and the relaying apparatus 30 a(step S106-1). As a result of the processing at step S104, thecommunication session (the second communication session sed12illustrated in FIG. 4) to transmit and receive telephone conversationdata is established between the relaying apparatus 30 a and theconversion system 80 (step S106-2). As a result of the processing atstep S105, the communication session (the third communication sessionsed13 illustrated in FIG. 4) to transmit and receive telephoneconversation data is established between the conversion system 80 andthe destination terminal (terminal 10 da) (step S106-3).

The following describes processing to transmit and receive telephoneconversation data for a telephone conversation such a teleconference,for example, between the requester terminal and the destination terminalwith reference to FIG. 24. FIG. 24 is a sequence diagram illustratingprocessing in which telephone conversation data is transmitted andreceived between the dedicated terminal A and the non-dedicated terminalD.

The requester terminal (terminal 10 aa) transmits image data of asubject imaged by the image capturing unit 14, and sound data of a soundreceived by the sound input unit 15 a to the relaying apparatus 30 afrom the transmitting-receiving unit 11 through the communicationnetwork 2 using the communication session sed11 (step S121). In thesecond communication pattern, the high image quality image data composedof three pieces of image data of low resolution, medium resolution, andhigh resolution illustrated in FIG. 3 and the sound data are transmittedin the same manner as the first communication pattern. As a result, inthe relaying apparatus 30 a, the transmitting-receiving unit 31 receivesthe image data composed of three pieces of different resolution imagedata and the sound data.

The relaying apparatus 30 a transmits the high quality image datacomposed of the three pieces of image data and the sound data to theconversion system 80 from the transmitting-receiving unit 31 through thecommunication network 2 using the communication session sed12 (stepS122). As a result, in the conversion system 80, thetransmitting-receiving unit 81 receives the image data composed of threepieces of different resolution image data and the sound data.

The communication scheme conversion unit 82 of the conversion system 80converts the image data composed of three pieces of different resolutionimage data from the communication scheme used by the requester terminal(terminal 10 aa) into that used by the destination terminal (terminal 10da) on the basis of the conversion rule preliminarily stored in thestorage unit 8000 (step S123). With the conversion of the communicationscheme, the image data composed of three pieces of different resolutionimage data (high resolution, medium resolution, and low resolution data)illustrated in FIG. 3 is converted into the image data of a singleresolution (medium resolution) illustrated in FIG. 5.

The conversion system 80 transmits the sound data and the mediumresolution image data to the terminal 10 da from thetransmitting-receiving unit 81 through the communication network 2 usingthe communication session sed13 (step S124). As a result, thetransmitting-receiving unit 11 of the destination terminal (terminal 10da) receives the sound data and the medium resolution image data.

As illustrated in FIG. 24, when the destination terminal (terminal 10da) transmits image data and sound data to the requester terminal(terminal 10 aa), the destination terminal (terminal 10 da) transmitsthe sound data and the medium resolution image data to the conversionsystem 80 from the transmitting-receiving unit 11 through thecommunication network 2 using the communication session sed13 (stepS125). As a result, the transmitting-receiving unit 81 of the conversionsystem 80 receives the sound data and the medium resolution image data.

The communication scheme conversion unit 82 of the conversion system 80converts the sound data and the medium resolution image data from thecommunication scheme used by the destination terminal (terminal 10 da)to that used by the requester terminal (terminal 10 aa) on the basis ofthe conversion rule preliminarily stored in the storage unit 8000 (stepS126).

FIGS. 25A to 25C are conceptual diagrams illustrating the image qualityof the image data having been converted by the conversion system. Atstep S126, the image data of a single resolution (medium resolution)illustrated in FIG. 5 is converted into the low resolution image dataillustrated in FIG. 25A, the medium resolution image data illustrated inFIG. 25C, and the low-medium resolution image data, which resolution isa medium between the medium resolution and the low resolution,illustrated in FIG. 25B. Because the medium resolution image data istransmitted from the destination terminal (terminal 10 da) serving asthe non-dedicated terminal D, the conversion system 80 cannot convertthe received medium resolution image data into image data having aresolution as high as that of the image data received at step S122. Theconversion system 80 thus converts the received medium resolution imagedata into the medium resolution image data, which is the highestresolution, the low-medium resolution image data, and the low resolutionimage data.

The conversion system 80 transmits the sound data and the image datacomposed of the three different resolution image data to the relayingapparatus 30 a from the transmitting-receiving unit 81 through thecommunication network 2 using the communication session sed12 (stepS127). As a result, in the relaying apparatus 30 a, thetransmitting-receiving unit 31 receives the sound data and the imagedata composed of three pieces of different resolution image data. Therelaying apparatus 30 a transmits the sound data and the image datacomposed of three pieces of different resolution image data to therequester terminal (terminal 10 aa) from the transmitting-receiving unit31 through the communication network 2 using the communication sessionsed11 (step S128). As a result, in the requester terminal (terminal 10aa), the transmitting-receiving unit 11 receives the sound data and theimage data composed of three pieces of different resolution image data.

The following describes a third communication pattern in which when atelephone conversation is made between the dedicated terminal A (anexample of the first communication terminal) and the dedicated terminalA (an example of the second communication terminal) and they are talkingwith teach other as illustrated in FIG. 21, another non-dedicatedterminal D joins the telephone conversation as a participation requestterminal. FIG. 26 is a sequence diagram illustrating processing ofcausing the non-dedicated terminal to join the telephone conversation.In this case, the participation request terminal is the terminal 10 db.

As illustrated in FIG. 26, the transmitting-receiving unit 11 of theparticipation request terminal (terminal 10 db) transmits, to theconversion system 80, the session start instruction informationindicating the instruction to start the communication session (stepS141). As a result, the transmitting-receiving unit 81 of the conversionsystem 80 receives the session start instruction information and the IPaddress of the non-dedicated terminal D serving as the participationrequest terminal. The session start instruction information includes theterminal ID “01aa” of the dedicated terminal A (in this case, theterminal 10 aa) as a target terminal with which the participationrequest terminal (terminal 10 db) tries to make a communication. Theterminal ID “01aa” is input or set to the participation request terminal(terminal 10 db) by a user of the participation request terminal(terminal 10 db).

The transmitting-receiving unit 81 of the conversion system 80transmits, to the management system 50, session ID request informationindicating a request for the session ID of the communication session(step S142). As a result, the transmitting-receiving unit 51 of themanagement system 50 receives the session ID request information and theIP address of the conversion system 80. The session ID requestinformation includes the terminal ID “01aa” received at step S141.

The storage-read processing unit 59 of the management system 50 searchesthe session management table (refer to FIG. 15) using the terminal ID“01aa” received at step S142 as a searching key, and reads the sessionID “se01” that identifies the communication session in which theterminal 10 aa indicated by the terminal ID “01aa” is busy (step S143).

The transmitting-receiving unit 51 of the management system 50transmits, to the conversion system 80, the session ID obtained by theprocessing at step S143 (step S144). As a result, thetransmitting-receiving unit 81 of the conversion system 80 receives thesession ID. The transmitting-receiving unit 81 of the conversion system80 establishes the third communication session sed13 to transmit andreceive telephone conversation data between itself and the relayingapparatus 30 a using the session ID received at step S144 (step S145-1).In the same manner, the transmitting-receiving unit 81 establishes afourth communication session sed14 to transmit and receive telephoneconversation data between itself and the participation request terminal(terminal 10 db) (step S145-2). As a result, the participation requestterminal can also join the telephone conversation even if theparticipation request terminal is the non-dedicated terminal D.

Advantages of Embodiment

As described above in the embodiment, by using a terminal ID of a targetterminal (the dedicated terminal A), which is received from aparticipation request terminal (the non-dedicated terminal D) throughthe conversion system 80, the management system 50 reads a session IDindicating that the target terminal is busy, (refer to step S143) andtransmits the session ID to the conversion system 80 (refer to stepS144). With this configuration, even if the communication scheme used bya communication terminal that is having a communication is differentfrom the communication scheme used by a communication terminal trying tojoin the communication, the communication terminal trying to join thecommunication can easily join the communication.

The session initialization request information transmitted to therelaying apparatus 30 a from the management system 50 includes the IPaddress of each of the requester terminal, the conversion system 80, andthe destination terminal. As a result, the relaying apparatus 30 a cantransmit the session start instruction information to the IP address ofthe requester terminal and transmit the session start instructioninformation including the IP address of the destination terminal to theIP address of the conversion system 80. Consequently, the conversionsystem 80 can transmit the session start instruction information to theIP address of the destination terminal.

The session initialization request information transmitted by themanagement system 50 as described above enables the first communicationsession sed11 to be established between the relaying apparatus 30 andthe requester terminal, the second communication session sed12 to beestablished between the relaying apparatus 30 and the conversion system80, and the third communication session sed13 to be established betweenthe conversion system 80 and the destination terminal. The embodimentthus has an advantage of enabling a telephone conversation to beachieved even if the requester terminal and the destination terminal usedifferent communication schemes because the conversion system 80mutually converts the communication schemes of the telephoneconversation data.

Additional Explanation of Embodiment

In the embodiment, the requester terminal or the dedicated terminal A isdescribed as an example of the first communication terminal while thedestination terminal or the non-dedicated terminal D is described as anexample of the second communication terminal. The examples, however, arenot limited to those. The destination terminal or the non-dedicatedterminal D may be an example of the first communication terminal whilethe requester terminal or the dedicated terminal A may be an example ofthe second communication terminal.

In the embodiment, the third communication pattern is described as acase where a participation request is made when a telephone conversationis made between the dedicated terminals A (in the first communicationpattern) as illustrated in FIG. 21. The participation request, however,may also be made when a telephone conversation is made between thededicated terminal A and the non-dedicated terminal D (in the secondcommunication pattern) as illustrated in FIG. 23.

The telephone conversation data is an example of the communication data.Examples of the communication data include file data of text and images.The telephone conversation terminal 10 is an example of thecommunication terminal. Examples of the communication terminal includean information processing terminal that transmits and receives the filedata in addition to the terminal that performs a telephone conversation.The telephone conversation management system 50 is an example of acommunication management system. Examples of the communicationmanagement system include a file management system that managesprocessing on the file data in addition to the system that managestelephone conversations. The telephone conversation system 1 is anexample of a communication system. The communication system includes thecommunication terminal and the communication management system.

In the embodiment, the management system 50 manages the communicationscheme information using the terminal information management table(refer to FIG. 12). The management manner, however, is not limited tothis example. The requester terminal may manage the communication schemeinformation of the destination terminal.

This structure enables the requester terminal (terminal 10 aa) totransmit, to the management system 50, the communication schemeinformation by including it in the start request information togetherwith the terminal IDs of the requester terminal and the destinationterminal at step S42 illustrated in FIG. 19. In this case, at step S41of FIG. 19, the display control unit 16 may cause the display 120 todisplay a selection screen for selecting the non-dedicated terminalserving as the destination of a telephone conversation and prompt a userto select the destination.

When the destination is selected from the selection screen, therequester terminal (terminal 10 aa) transmits, to the management system,the start request information that includes the information(communication scheme information) indicating that the destinationterminal ID is associated with the non-dedicated terminal at step S42 ofFIG. 19. In this case, the management system 50 does not need to performthe processing at step S45-1 of FIG. 20. The management system 50determines that the communication scheme used by the destinationterminal is not the dedicated one on the basis of the communicationscheme information included in the start request information (No at stepS45-2 of FIG. 20), and then the processing proceeds to step S45-3 ofFIG. 20.

A user is not always required to select the destination from theselection screen. For example, when a user already grasps positioninformation about the destination terminal, the user may input theposition information (e.g., the IP address) about the destinationterminal to the operation input reception unit 12. In this case, therequester terminal transmits, to the management system 50 at step S42,the start request information that includes the position informationabout the destination terminal and the information (communication schemeinformation) indicating that the destination terminal is thenon-dedicated terminal, instead of the terminal ID of the destinationterminal. In the management system 50, the determination unit 55determines, at step S45-2, that the destination terminal indicated bythe position information is not the dedicated terminal, and then theprocessing proceeds to the processing at step S45-3. At step S45-3, thestorage-read processing unit 59 extracts the position information aboutthe conversion system 80 on the basis of the position information aboutthe non-dedicated terminal, and then the processing proceeds to theprocessing at step S101.

The terminal ID may be preliminarily stored in the terminal 10 as thefactory setting, for example, or may be input by a user.

The relaying apparatus 30, the management system 50, the conversionsystem 80, the program supply system 90, and the maintenance system 100in the embodiment may be structured by a single computer. The units(function or operations) of them may be divided and the divided unitsmay be structured by a plurality of computers each allocated for anyunit. When the program supply system 90 is structured by a singlecomputer, a program transmitted by the program supply system 90 may betransmitted as a plurality of divided modules or transmitted withoutbeing divided. When the program supply system 90 is structured by aplurality of computers, a program may be transmitted from the computersas a plurality of divided modules.

In the embodiment, the protocol of the instant messenger (or theextended version of the protocol of the instant messenger) and SIP aredescribed as an example used in a case where the call control schemesdiffer between the terminals. The combination of the call controlschemes is not limited to this example, and any combination isapplicable as long as the call control schemes differ between theterminals. For example, a combination of the protocol of the instantmessenger (or the extended version of the protocol of the instantmessenger) and H.323 may be applicable. For another example, acombination of the protocol of the instant messenger and the extendedversion of the protocol of the instant messenger may also be applicable.

The recording medium, such as a CD-ROM, that stores therein therespective programs of the embodiment, the HD 204 that stores thereinthe programs, and the program supply system 90 including the HD 204 canbe provided as program products domestically or overseas.

In the embodiment, as an example of the quality of an image of the imagedata relayed by the relaying apparatus 30, attention is paid to theresolution of the image of the image data and the resolution is managedby the quality change management table illustrated in FIG. 10 and thequality management table illustrated in FIG. 17. The image quality isnot limited to the resolution. As other examples of the quality,attention may be paid to a depth of image quality of the image data, asampling frequency of a sound in the sound data, and a bit length of asound in the sound data, and the quality may be managed. Sound data maybe transmitted and received by being divided with respect to threepieces of data having different resolutions (high resolution, mediumresolution, and low resolution).

In FIGS. 11, 13, and 15, the receiving date is managed. The managementitem is not limited to the receiving date. At least receiving time maybe managed in the receiving date.

In the embodiment, the IP address of the relaying apparatus 30 ismanaged in FIG. 11 while the IP address of the terminal 10 is managed inFIG. 13. The management item, however, is not limited to the IP address.Each fully qualified domain name (FQDN) of the relaying apparatus 30 andthe terminal 10 may be managed as the position information foridentifying the relaying apparatus 30 on the communication network 2 orthe position information for identifying the terminal 10 on thecommunication network 2. In this case, the IP address corresponding tothe FQDN is acquired by a known domain name system (DNS) server.

In the embodiments, the teleconference system is described as an exampleof the telephone conversation system 1. The telephone conversationsystem 1, however, is not limited to be applied to the teleconferencesystem. The telephone conversation system 1 may be applicable to atelephone system such as an Internet protocol (IP) telephone and anInternet telephone. The telephone conversation system 1 may be a carnavigation system. In this case, one terminal 10 corresponds to a carnavigation system mounted on a vehicle while the other terminal 10corresponds to a management terminal or a management server of amanagement center that manages the car navigation or another carnavigation system mounted on another vehicle. The telephone conversationsystem 1 may be a communication system of mobile phones. In this case,the terminal 10 corresponds to the mobile phone, for example.

In the embodiment, image data and sound data are described as examplesof the telephone conversation data. The data, however, is not limited tothe image data and the sound data. Touch data may be applicable. In thiscase, a sense of touch obtained by a user at one terminal is transmittedto the other terminal through a telephone conversation. The telephoneconversation data may be olfaction (smell) data. In this case, an aroma(smell) at one terminal is transmitted to the other terminal through atelephone conversation. The telephone conversation data may be at leastone piece of image data, sound data, touch data, and olfaction data.

In the embodiment, the teleconference is held using the telephoneconversation system 1. The telephone conversation system 1, however, isnot limited to be used for the teleconference. The telephoneconversation system 1 may be used for meetings, general conversationsamong family members or friends or information supply in one direction.

The communication management system according to an aspect of theinvention receives terminal identifying information about acommunication terminal that is having a communication from a conversionsystem, which mutually converts a communication scheme of communicationdata transmitted from one communication terminal and anothercommunication scheme of communication data transmitted from anothercommunication terminal. The communication management system thentransmits session identifying information that is associated with thereceived terminal identifying information to the conversion system. Withthis configuration, even if the communication scheme of a communicationterminal trying to join a communication is different from thecommunication scheme of a plurality of communication terminals that ishaving the communication, the communication terminal trying to join thecommunication can join the communication.

The present invention can be implemented in any convenient form, forexample using dedicated hardware, or a mixture of dedicated hardware andsoftware. The present invention may be implemented as computer softwareimplemented by one or more network processing apparatus. The network cancomprise any conventional terrestrial or wireless communicationsnetwork, such as the Internet. The processing apparatus can compromiseany suitably programmed apparatuses such as a general purpose computer,personal digital assistant, mobile telephone (such as a WAP or3G-compliant phone) and so on. Since the present invention can beimplemented as software, each and every aspect of the present inventionthus encompasses computer software implemental on a programmable device.The computer software can be provided to the programmable device usingany storage medium for storing processor readable code such as a floppydisk, hard disk, CD ROM, magnetic tape device or solid state memorydevice.

The hardware platform includes any desired kind of hardware resourcesincluding, for example, a central processing unit (CPU), a random accessmemory (RAM), and a hard disk drive (HDD). The CPU may be implemented byany desired kind of any desired number of processor. The RAM may beimplemented by any desired kind of volatile or non-volatile memory. TheHDD may be implemented by any desired kind of non-volatile memorycapable of storing a large amount of data. The hardware resources mayadditionally include an input device, an output device, or a networkdevice, depending on the type of the apparatus. Alternatively, the HDDmay be provided outside of the apparatus as long as the HDD isaccessible. In this example, the CPU, such as a cache memory of the CPU,and the RAM may function as a physical memory or a primary memory of theapparatus, while the HDD may function as a secondary memory of theapparatus.

Although the invention has been described with respect to specificembodiments for a complete and clear disclosure, the appended claims arenot to be thus limited but are to be construed as embodying allmodifications and alternative constructions that may occur to oneskilled in the art that fairly fall within the basic teaching herein setforth.

What is claimed is:
 1. A system comprising: a memory configured to storesession identification information for identifying a session that isestablished between a first communication terminal and a secondcommunication terminal based on a first communication method through arelaying apparatus and identification information of the firstcommunication terminal and the second communication terminal inassociation with each other, the first communication terminal or thesecond communication terminal being configured to transmit communicationdata based on the first communication method; a receiver configured toreceive session start instruction information for instructing a start ofa session from a third communication terminal that transmitscommunication data to another communication terminal based on a secondcommunication method different from the first communication method whilethe communication data is transmitted using the session establishedbetween the first communication terminal and the second communicationterminal based on the first communication method through the relayingapparatus, the session start instruction information including at leastthe identification information of the first communication terminalwithout including the session identification information; and processingcircuitry configured to identify session identification information foridentifying a session being established between the first communicationterminal and the second communication terminal based on theidentification information of the first communication terminal includedin the session start instruction information, the session identificationinformation being associated with the identification information of thefirst communication terminal stored in the memory, wherein the thirdcommunication terminal that transmits the communication data based onthe second communication method is allowed to join the session beingestablished between the first communication terminal and the secondcommunication terminal through the relaying apparatus and a conversionsystem that mutually converts the first communication method and thesecond communication method, based on the session identificationinformation identified by the processing circuitry.
 2. The systemaccording to claim 1, wherein the identification information of thefirst communication terminal included in the session start instructioninformation received from the third communication terminal isinformation input to the third communication terminal by a user of thethird communication terminal.
 3. The system according to claim 1,wherein the memory further stores operation states of the firstcommunication terminal and the second communication terminal under thefirst communication method but does not store an operation state of thethird communication terminal under the second communication method. 4.The system according to claim 1, wherein each of the first and secondcommunication methods includes at least a session control protocol and avideo coding method, and the first communication method differs from thesecond communication method in a type of the video coding method.
 5. Thesystem according to claim 4, wherein the video coding method included inthe first communication method is H.264/scalable video coding, and thevideo coding method included in the second communication method isH.264/advanced video coding.
 6. The system according to claim 1, furthercomprising: the conversion system that includes the receiver; and amanagement system that includes the processing circuitry, wherein theconversion system further includes a transmitter configured to transmit,to the management system, session identification information requestinformation that indicates a request for the session identificationinformation for identifying a session which the first communicationterminal is joining in response to receiving the session startinstruction information, the conversion system receives, through thereceiver, the session identification information that is identified bythe processing circuitry of the management system in response toreceiving the session identification information request information,and the conversion system further allows the third communicationterminal to join the session being established between the firstcommunication terminal and the second communication terminal through notonly the relaying apparatus but also the conversion system, based on thesession identification information received by the receiver.
 7. Amethod, implemented by a system, comprising: storing, by a memory,identification information for identifying a session that is establishedbetween a first communication terminal and a second communicationterminal based on a first communication method through a relayingapparatus and identification information of the first communicationterminal and the second communication terminal in association with eachother, the first communication terminal or the second communicationterminal being configured to transmit communication data based on thefirst communication method; receiving, by a receiver, session startinstruction information for instructing a start of a session from athird communication terminal that transmits communication data toanother communication terminal based on a second communication methoddifferent from the first communication method while the communicationdata is transmitted using the session established between the firstcommunication terminal and the second communication terminal based onthe first communication method through the relaying apparatus, thesession start instruction information including at least theidentification information of the first communication terminal withoutincluding any session identification information; and identifying, byprocessing circuitry, session identification information for identifyinga session being established between the first communication terminal andthe second communication terminal based on the identificationinformation of the first communication terminal included in the sessionstart instruction information, the session identification informationbeing associated with the identification information of the firstcommunication terminal stored in the memory, wherein the thirdcommunication terminal that transmits the communication data based onthe second communication method is allowed to join the session beingestablished between the first communication terminal and the secondcommunication terminal through the relaying apparatus and a conversionsystem that mutually converts the first communication method and thesecond communication method, based on the session identificationinformation identified by the processing circuitry.
 8. The methodaccording to claim 7, wherein the identification information of thefirst communication terminal included in the session start instructioninformation received from the third communication terminal isinformation input to the third communication terminal by a user of thethird communication terminal.
 9. The method according to claim 7,wherein the memory further stores operation states of the firstcommunication terminal and the second communication terminal under thefirst communication method but does not store an operation state of thethird communication terminal under the second communication method. 10.The method according to claim 7, wherein each of the first and secondcommunication methods includes at least a session control protocol and avideo coding method, and the first communication method differs from thesecond communication method in a type of the video coding method. 11.The method according to claim 10, wherein the video coding methodincluded in the first communication method is H.264/scalable videocoding, and the video coding method included in the second communicationmethod is H.264/advanced video coding.
 12. A communication managementsystem comprising: a memory configured to store session identificationinformation for identifying a session that is established between afirst communication terminal and a second communication terminal basedon a first communication method through a relaying apparatus andidentification information of the first communication terminal and thesecond communication terminal in association with each other, the firstcommunication terminal or the second communication terminal beingconfigured to transmit communication data based on the firstcommunication method; a receiver configured to receive theidentification information of the first communication terminal, withoutincluding any session identification information, from a conversionsystem that mutually converts the first communication method and thesecond communication method while the communication data is transmittedusing the session established between the first communication terminaland the second communication terminal based on the first communicationmethod through the relaying apparatus, the identification information tobe received being transmitted from a third communication terminal thattransmits communication data to another communication terminal based ona second communication method different from the first communicationmethod; processing circuitry configured to identify sessionidentification information for identifying a session being establishedbetween the first communication terminal and the second communicationterminal based on the identification information of the firstcommunication terminal received from the conversion system, the sessionidentification information being associated with the identificationinformation of the first communication terminal stored in the memory;and a transmitter configured to transmit the identified sessionidentification information to the conversion system so that the thirdcommunication terminal joins the session being established between thefirst communication terminal and the second communication terminalthrough the relaying apparatus and the conversion system.
 13. Thecommunication management system according to claim 12, wherein theidentification information of the first communication terminal receivedfrom the conversion system is information input to the thirdcommunication terminal by a user of the third communication terminal.14. The system according to claim 12, wherein the memory further storesoperation states of the first communication terminal and the secondcommunication terminal under the first communication method but does notstore an operation state of the third communication terminal under thesecond communication method.
 15. The system according to claim 12,wherein each of the first and second communication methods includes atleast a session control protocol and a video coding method, and thefirst communication method differs from the second communication methodin a type of the video coding method.
 16. The system according to claim15, wherein the video coding method included in the first communicationmethod is H.264/scalable video coding, and the video coding methodincluded in the second communication method is H.264/advanced videocoding.
 17. A method, implemented by a communication management system,comprising: storying, by a memory, session identification informationfor identifying a session that is established between a firstcommunication terminal and a second communication terminal based on afirst communication method through a relaying apparatus andidentification information of the first communication terminal and thesecond communication terminal in association with each other, the firstcommunication terminal or the second communication terminal beingconfigured to transmit communication data based on the firstcommunication method; receiving, by a receiver, the identificationinformation of the first communication terminal, without including anysession identification information, from a conversion system thatmutually converts the first communication method and the secondcommunication method while the communication data is transmitted usingthe session established between the first communication terminal and thesecond communication terminal based on the first communication methodthrough the relaying apparatus, the identification information to bereceived being transmitted from a third communication terminal thattransmits communication data to another communication terminal based ona second communication method different from the first communicationmethod; identifying, by processing circuitry, session identificationinformation for identifying a session being established between thefirst communication terminal and the second communication terminal basedon the identification information of the first communication terminalreceived from the conversion system, the session identificationinformation being associated with the identification information of thefirst communication terminal stored in the memory; and transmitting, bya transmitter, the identified session identification information to theconversion system so that the third communication terminal joins thesession being established between the first communication terminal andthe second communication terminal through the relaying apparatus and theconversion system.
 18. The method according to claim 17, wherein theidentification information of the first communication terminal receivedfrom the conversion system is information input to the thirdcommunication terminal by a user of the third communication terminal.19. The method according to claim 17, wherein the memory further storesoperation states of the first communication terminal and the secondcommunication terminal under the first communication method but does notstore an operation state of the third communication terminal under thesecond communication method.
 20. The method according to claim 17,wherein each of the first and second communication methods includes atleast a session control protocol and a video coding method, and thefirst communication method differs from the second communication methodin a type of the video coding method.
 21. The method according to claim20, wherein the video coding method included in the first communicationmethod is H.264/scalable video coding, and the video coding methodincluded in the second communication method is H.264/advanced videocoding.